1. Field of the Invention
The present invention relates to an adjustment linkage for a tilting and telescoping steering column assembly in which an actuating lever for tilting and telescoping pivots with the steering column while positioning adjustments are made.
2. Background Art
Vehicle steering column assemblies sometimes include tilting and telescoping features for steering wheel adjustment. These adjustment features typically include separate levers for tilting and telescoping adjustment.
U.S. Pat. No. 6,237,439 provides an improved steering column assembly with a single release lever which actuates tilting and telescoping movement of the steering column, and in which the tilt and telescope features are fully contained within the steering column assembly, thereby eliminating the need for additional attachment steps when assembling the steering column assembly into the vehicle.
It is further desirable to provide a tilting and telescoping steering column assembly in which an actuating lever moves with the tilting and telescopic adjustment motion of the steering wheel so that the operator does not have to take their hands off of the steering wheel while adjusting the steering wheel position.
The present invention provides a tilting and telescoping steering column assembly including an adjustment lever and adjustment features which are incorporated into a modular, integrated steering column assembly. The system includes an adjustment linkage which allows the driver to keep their hands on the steering wheel while releasing the steering column for tilt and telescopic adjustments, with the ability to release one such adjustment at a time.
This adjustment capability is achieved via the linkage which includes a slidable link, arcuate slot and slot follower pin which enable translation of adjustment motions through the tilting axis of the steering column assembly so that the adjustment lever may tilt with the steering wheel.
More specifically, the invention provides a tilting and telescoping steering column assembly including a steering column shaft pivotally connected to an intermediate shaft at a tilt pivot joint. A tilt locking mechanism is operatively associated with the steering column shaft to allow selective tilting adjustment of the steering column shaft. A telescope locking mechanism is operatively associated with the intermediate shaft to allow selective telescopic adjustment of the steering column shaft. A linkage includes a first portion which is pivotally movable with the steering column shaft, a second portion operatively connected to the tilt and telescope locking mechanisms, and a slidable link member between the first and second portions adjacent the tilt pivot joint. The slidable link member is connected to the first portion by an arcuate slot member and slot follower pin to accommodate pivotal movement of the first portion with respect to the second portion. An actuator lever is connected to the linkage and pivotable with the steering column shaft during tilting adjustment of the steering column shaft.
Preferably, the steering column shaft is pivotally connected to a sleeve about a pivot axis and extends out of the sleeve to receive a steering wheel. The sleeve is slidably positioned within a housing and includes a telescope gear member. The housing is configured for attachment to a vehicle support structure, and includes an internal rack extending longitudinally within the housing for engagement with the telescope gear member. The telescope gear member is lockable and unlockable by a pawl for selective telescoping of the sleeve with respect to the housing.
Preferably, the arcuate slot member is integral with the slidable link member, and the slidable link member is intersected by the pivot axis of the tilt pivot joint.
The pawl, which forms the telescope locking mechanism, includes a dwell slot formed therein, and the second portion of the linkage includes a dwell pin cooperating with the dwell slot to delay unlocking of the telescope gear member while the tilt locking mechanism is unlocked to allow tilting of the steering column shaft.
Preferably, a mechanical advantage arm is connected to the steering column shaft and extends into the sleeve in a direction opposite the steering column shaft with respect to the pivot axis. The arm has a distal end with at least one tooth. The tilt locking mechanism is secured to the sleeve and engageable with the tooth to lock the arm and steering column shaft in a desired tilt position. The tilt locking mechanism includes a pivotable lock member connected to the second portion and having upper and lower teeth engageable with the tooth on the arm. The lock member is pivotable between a first position in which the lower teeth are engaged, a second position in which no teeth are engaged to allow tilting of the steering column shaft, and a third position in which the upper teeth are engaged.
The telescope gear member preferably includes an inner gear which is engageable with the pawl and first and second outer gears engaged with the internal rack.
An energy dissipation device is positioned between the inner and outer gears to dissipate energy when the outer gears are forcibly rotated with respect to the inner gear. The energy dissipation device includes a pin connected to the inner gear and engaged with slots formed on first and second steel disks which are connected to the first and second outer gears, respectively, such that forcible rotation of the outer gears causes the disks to cold form as the pin is forced through the slots.
A plurality of roller devices are provided on the telescope sleeve to facilitate telescoping movement of the sleeve with respect to the housing. Each roller device includes first and second axially offset washers which are configured to counter-rotate during telescoping movement of the sleeve. The washers are positioned on axles which are rotationally spring-biased to force the washers against opposing walls of the respective channel which receives the washers.
Accordingly, an object of the invention is to provide an improved tilting and telescoping steering column assembly in which a tilt/telescope adjustment lever is tiltable with the steering column shaft so that the driver does not have to remove his or her hands from the steering wheel to actuate the lever and adjust the steering wheel.
The above object and other objects, features, and advantages of the present invention are readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings.